A customer has said that when they receive their invoice. They cant pay it from the link in the email. Do you know how this can be fixed? Many thanks

We can let your customer perform a troubleshooting steps to pay the invoices successfully, tombascoffee.

It can be that the browser of your customer is holding too much cache. You can share these steps with your customers, so they'll be able to pay the invoices without encountering unexpected behavior.
 

1. Click the Reload icon or press CTRL + F5 to refresh QuickBooks.
2. You can go back to the part where you encounter the error to see if you are still getting the error message.
3. If it works in private browsing, clear the cache of your previous browser. Alternatively, you can use other compatible browsers in QBO.
4. Restart the browser.

Please let me know if you have other questions by adding a comment below. I'll help you further in case you need further assistance with QBO. Thanks!